Re: [PATCH v2 2/4] powerpc/mm/radix: Free PUD table when freeing pagetable

["Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>]

On 7/8/20 7:42 AM, Michael Ellerman wrote:
> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
>> From: Bharata B Rao <bharata@linux.ibm.com>
>>
>> remove_pagetable() isn't freeing PUD table. This causes memory
>> leak during memory unplug. Fix this.
> 

Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()")


> Fixes: ??
> 
> cheers
> 
>> Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>>   arch/powerpc/mm/book3s64/radix_pgtable.c | 16 ++++++++++++++++
>>   1 file changed, 16 insertions(+)
>>
>> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
>> index 80be96d3018f..af57604f295f 100644
>> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
>> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
>> @@ -708,6 +708,21 @@ static void free_pmd_table(pmd_t *pmd_start, pud_t *pud)
>>   	pud_clear(pud);
>>   }
>>   
>> +static void free_pud_table(pud_t *pud_start, p4d_t *p4d)
>> +{
>> +	pud_t *pud;
>> +	int i;
>> +
>> +	for (i = 0; i < PTRS_PER_PUD; i++) {
>> +		pud = pud_start + i;
>> +		if (!pud_none(*pud))
>> +			return;
>> +	}
>> +
>> +	pud_free(&init_mm, pud_start);
>> +	p4d_clear(p4d);
>> +}
>> +
>>   struct change_mapping_params {
>>   	pte_t *pte;
>>   	unsigned long start;
>> @@ -882,6 +897,7 @@ static void __meminit remove_pagetable(unsigned long start, unsigned long end)
>>   
>>   		pud_base = (pud_t *)p4d_page_vaddr(*p4d);
>>   		remove_pud_table(pud_base, addr, next);
>> +		free_pud_table(pud_base, p4d);
>>   	}
>>   
>>   	spin_unlock(&init_mm.page_table_lock);
>> -- 
>> 2.26.2